Rutherfordium is a chemical element with symbol Rf and atomic number 104, named in honor of New Zealand physicist Ernest Rutherford. It is a synthetic element and radioactive; the most stable known isotope, 267Rf, has a half-life of approximately 1.3 hours. In the 1960s, small amounts of rutherfordium were produced in laboratories in the former Soviet Union and in California, USA. The priority of the discovery and therefore the naming of the element was disputed between Soviet and American scientists, and it was not until 1997 that IUPAC established rutherfordium as the official name for the element.